1. Field of the Invention
This invention relates to block copolymers of polyphenylene oxides and sterically hindered dihydric phenols. These formal-coupled block polymers can be molded, calendered, or extruded as films, sheets, fibers, laminates or other useful articles of manufacture.
2. Description of the Prior Art
Polyphenylene oxides having an average hydroxyl group per molecule of 1.0 or less, are described in A. S. Hay's U.S. Pat. Nos. 3,306,879; 3,914,266; and 4,028,341; among others.
Polyphenylene oxides having an average hydroxyl group per molecule greater than zero including 2.0 or less are described in D. M. White's U.S. Pat. Nos. 4,140,675 and 4,234,706 among others.
Polyformals are described in R. Barclay, Jr."s U.S. Pat. No. 3,069,386, A. S. Hay's copending U.S. Ser. No. 858,040, filed Nov. 6, 1978, and G. R. Loucks et al. Ser. No. 889,397, filed Mar. 23, 1978.